Understanding the flow of water through Earth’s rivers is crucial for managing freshwater resources and comprehending the planet’s water cycle. A recent study led by NASA researchers offers new estimates of river water volume, flow rates, and fluctuations over time. This study sheds light on regions facing water depletion due to heavy usage, such as the Colorado River basin, the Amazon basin, and the Orange River basin. The novel methodology used for this study combines stream-gauge measurements with computer models of millions of river segments worldwide.
The study estimates that the total volume of water in Earth’s rivers from 1980 to 2009 averaged around 539 cubic miles, equivalent to half of Lake Michigan’s water. Despite rivers holding only a small fraction of the planet’s water, they have been essential to human civilization for centuries. Previous estimates of river water outflows into the ocean have been abundant, but estimates concerning the volume of water stored in rivers have been scarce and uncertain. This lack of data complicates the management of freshwater resources, especially with growing populations and the impacts of climate change.
The Amazon basin emerges as a key region with the highest river storage, holding around 204 cubic miles of water. A significant portion of the global river discharge into the ocean also comes from the Amazon basin, accounting for 18% of the total discharge from 1980 to 2009. The study pointed out regions like the Colorado, Amazon, and Orange river basins, along with the Murray-Darling basin in Australia, showing negative flows indicating intensive human water usage.
For decades, estimates of Earth’s total river water have been based on a 1974 United Nations figure, lacking variation over time. Obtaining better estimates has been challenging due to the limited observations of rivers, particularly in remote areas. The study addressed these challenges by combining simulated runoff data with gauge measurements from various locations, correcting inconsistencies to develop more accurate estimates of river water storage and discharge rates.
The results of this study provide an essential foundation for future research on Earth’s water cycle. The utilization of a consistent methodology allows for comparisons between different regions regarding river water storage and discharge rates. This information is vital for water resource management and understanding the impacts of human activity on river systems. Moving forward, continued research using advanced technologies like the Surface Water and Ocean Topography (SWOT) satellite will further enhance our knowledge of Earth’s water dynamics.
The study conducted by NASA researchers sheds light on the complex nature of Earth’s river water fluctuations. By combining innovative methodologies with advanced technologies, researchers can obtain more accurate estimates of river water storage and flow rates. This information is essential for sustainable water management practices and addressing the challenges posed by a changing climate and growing populations.